Czech scientist named among Time’s 100 Most Influential People for HIV breakthrough
Time magazine has named Tomáš Cihlář, a Czech virologist at the US biopharmaceutical company Gilead, among the 100 Most Influential People of 2025, alongside biochemist Wesley Sundquist of the University of Utah. Their work focuses on developing drugs that protect against HIV.
Today, access to antiviral medications can turn an HIV infection, including AIDS, from a fatal disease into a chronic condition. One key drug, Viread, was developed in the early 2000s with crucial input from the Czech scientist Antonín Holý. His former student and assistant, Tomáš Cihlář, continues in his professor’s footsteps.
With no effective HIV vaccine yet, prevention remains the focus of research, which is where Cihlář and Sundquist have made a major contribution. For over a decade, they have worked to turn the antiviral drug lenacapavir into a twice-yearly injection to help prevent HIV infection. As the WHO Director-General put it: “While an HIV vaccine remains elusive, lenacapavir is the next best thing.”
Cihlář explained lenacapavir’s uniqueness as an antiviral drug in an interview with Czech Radio in 2023:
“What makes it exceptional is that it can be given as an injection just once every six months. Patients no longer have to remember to take a pill every day, and many tell us that receiving an injection twice a year frees them from the constant daily reminder that they are living with the virus.”
To allow for this new intake method, Sundquist laid the scientific foundations through his research into HIV’s capsid, the protein that protects the virus’s genetic material. When Cihlář visited his laboratory, he saw the potential and brought his findings to Gilead Sciences. There, his team extended the drug’s effect to six months, allowing patients to receive just two injections a year.
David Jilich, head of the HIV Centre at the Department of Infectious Diseases at Prague’s Bulovka University Hospital, explained why this is beneficial:
“The main advantage is not just convenience, but the reliability of the treatment regimen. The risk of not taking prescribed pills correctly and regularly is far greater with daily medication than when patients need to visit their healthcare provider ‘only’ twice a year.”
Lenacapavir injections crucially proved effective in preventing HIV infection. Gilead tested the drug in people not yet infected but at high risk, to see if the injections could stop infection. The results were very promising, showing 96–100% effectiveness at the time when Time published its April article naming Cihlář and Sundquist among the 100 most influential people of the year. The article also noted that, if approved, lenacapavir would be "the first twice-a-year injected drug to prevent HIV."
Approval followed just a couple months later. In June, the US Food and Drug Administration authorised injectable lenacapavir for HIV prevention, and in August the European Commission approved it for use on the European market. The World Health Organization has also recommended the drug, noting that it comes at a critical time, as HIV prevention efforts stagnate with 1.3 million new infections in 2024.
Tomáš Cihlář was born in Chomutov in north-west Czechia and studied in Prague. He now lives and works in California and has received numerous honours, including the Medal of Merit, awarded in 2020 by former president Miloš Zeman for his contribution to the development of remdesivir, which proved potentially effective in treating Covid-19.
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